Top Robotic Pool Cleaners: Choosing Chasing Models

Choosing a robotic pool cleaner comes down to matching the machine to the pool you have: its size, shape, surface, debris load, and how much handling you want to do. This guide compares the five Chasing models RoboticsSelect carries, the Hydro 3, Hydro 3S, Hydro 4 Corded, Hydro 4 Battery, and L1 Ultra, against each other so the tradeoffs are clear before you buy.

Which Chasing pool cleaner fits your pool?

Start with the pool size rating. Chasing rates the Hydro 3 for small pools of 861 to 1,076 square feet, with the best results around 861. The Hydro 3S covers small to medium pools up to about 1,614 square feet, and both Hydro 4 versions are rated for medium to large pools up to 1,614 square feet. The L1 Ultra is positioned for medium to large pools; Chasing states it cleans a 320-square-foot pool in around 30 minutes at close to 95 percent coverage.

Depth and surface are the same across the range: in-ground and above-ground pools from 1.6 to 9.8 feet deep, on concrete, vinyl, fiberglass, and tile. Every model climbs the walls and works the waterline, so the differences are in power source, navigation, and app control. If you are still deciding between cleaner types, start with the robotic pool cleaner buying guide.

How does each model navigate the pool?

The Hydro 3 follows a standard path with wall-climb sensors and does not plan its route. The Hydro 3S and both Hydro 4 versions use Chasing's HydroCurve S-shaped path planning, which sweeps the pool in straight back-and-forth lines. Chasing rates HydroCurve at up to 95 percent coverage, and on the Hydro 3S it states about 30 percent less overlap than a random-path cleaner, with a path that adapts to round, L-shaped, and freeform pools.

The L1 Ultra maps the pool before it cleans. A 360-degree LiDAR sensor (a spinning laser that measures distances) scans the pool's shape and builds a real-time map, and an AI camera recognizes debris such as leaves, sand, hair, and fine dust so the robot steers toward the areas that need attention. Height and depth sensors read steps, slopes, and changes in water depth, and built-in lighting lets it keep cleaning after dark.

Built-in battery, deck cable, buoy, or dock?

This is the choice that changes your routine most. The Hydro 3 and Hydro 3S have a built-in battery that charges through a port under a rubber cover on the unit; there is no buoy and no dock, and a full charge takes about 4 hours. The Hydro 4 Corded runs on continuous AC power from a pool-deck control box through a 49.2-foot anti-snag swivel cable. The Hydro 4 Battery swaps that cable for a detachable floating buoy on a 9.8-foot tether that charges on its own in about 4 hours. The L1 Ultra carries an onboard 11,000 mAh battery and recharges on a wireless dock that doubles as storage.

Model	Power source	Runtime per charge
Hydro 3	Built-in rechargeable battery, charged on the unit	Up to 200 minutes
Hydro 3S	Built-in 11,000 mAh battery, charged on the unit	Up to 200 minutes; up to 300 in Eco mode
Hydro 4 Corded	49.2-foot cable to a pool-deck control box	Unlimited (continuous AC power)
Hydro 4 Battery	Detachable floating battery buoy, 9.8-foot tether	Up to 3.5 hours (210 minutes)
L1 Ultra	Onboard 11,000 mAh battery, wireless charging dock	Up to 300 minutes (5 hours) in ECO mode

Choose the cable for long, back-to-back cycles on a large pool or heavy leaf drop, and plan on coiling it after each run; the control box needs a dry, sheltered spot on the deck and a GFCI outlet. Choose the buoy or a built-in battery for a clear deck. Every cordless Chasing model is listed in the cordless robotic pool cleaners collection.

The five Chasing models compared

Chasing Hydro 3: simple cordless cleaning for small pools

The Hydro 3 is the entry point. You pick a mode with the controls on the unit, lower it in, and it cleans for up to 200 minutes before docking at the pool edge when the cycle ends or the battery runs low. Two centrifugal pumps move up to 320 liters per minute (5,070 gallons per hour) through twin inlets. There is no app and no path planning, at 16.5 pounds it lifts out by hand, and it carries a 1-year limited warranty, one year less than the rest of the line.

Chasing Hydro 3S: planned coverage and app control

The Hydro 3S uses the same body, pumps, and basket as the Hydro 3 but adds HydroCurve navigation, four cleaning modes (Regular, Floor, Walls and Waterline, and Eco), and the Chasing app for weekly schedules, remote control, a water temperature readout, and over-the-air updates. Eco mode stretches a charge to 300 minutes, and side jets tilt the body up to 2 inches to hold a steady line at the waterline. Choose your mode before lowering it in, because the Bluetooth link drops once the unit is submerged.

Chasing Hydro 4 Corded: continuous power for larger pools

The Hydro 4 Corded is built for medium to large pools and for owners who do not want runtime to be the limit. It offers Auto, Floor, and Walls and Waterline modes with 1, 2, and 3 hour cycle presets, plus an Ultra setting that raises cleaning power by about 30 percent for heavy debris. Dual active PVC roller brushes scrub from the front and rear, and the app adds 360-degree manual steering, scheduled starts, and control while the unit is underwater. The robot weighs 14.3 pounds and the control box 3.3 pounds.

Chasing Hydro 4 Battery: the same platform without the cable

The Hydro 4 Battery shares the Hydro 4 Corded's pumps, rollers, basket, modes, and app steering, and swaps the deck cable for the floating buoy. A full buoy charge supports up to 3.5 hours of cleaning, and when the cycle ends the unit parks at the pool edge and floats to the surface for pickup. The 5.5-pound buoy is covered by the 2-year warranty alongside the drive and pump motors.

Chasing L1 Ultra: mapping, AI vision, and a wireless dock

The L1 Ultra is the most advanced model in the line. Its dual-pump system is rated at up to 504 liters per minute (8,000 gallons per hour) with three suction levels (ECO, Standard, and Ultra) and four modes (Auto, Floor, Wall, and Waterline). You can run it from on-device buttons, over Bluetooth nearby, or through Wi-Fi cloud control from anywhere. When a cycle ends or the battery drops below 5 percent, it surfaces at the pool edge or at a custom point you set in the app, then recharges on the plug-free dock. Set a weekly schedule and Chasing states it runs on its own for up to two weeks. At 22 pounds it is the heaviest of the five.

Filtration, debris, and app control

Every Chasing model uses a 4.1-liter basket with a 180-micron mesh. The Hydro 3, Hydro 3S, and both Hydro 4 versions use a dual-zone design that separates leaves and larger debris from fine sand and silt. The L1 Ultra's basket has a dual-opening anti-clog design, and Chasing offers an optional 50-micron plush-fabric basket for it that traps fine sand, pollen, and algae fragments; the Hydro 3S accepts an optional hyper-fine filter. Rinse the basket after every cycle, and expect a mid-cycle emptying when leaf load is heavy.

The Hydro 3 has no app. The Hydro 3S adds scheduling, remote control, and the water temperature display; the Hydro 4 models add 360-degree manual steering and mid-cycle mode changes; the L1 Ultra adds Wi-Fi cloud control, suction adjustment, and a custom surfacing point. None of them dispenses chemicals, so water chemistry still has to be maintained separately. For a side-by-side spec table of all five, see the Chasing comparison page.

Warranty, support, and buying from an authorized dealer

A pool robot works in water, chemicals, sun, and grit, so warranty terms belong in the decision. The Hydro 3 carries Chasing's 1-year limited warranty on the main unit and core systems; the Hydro 3S, Hydro 4 Corded, Hydro 4 Battery, and L1 Ultra carry 2-year limited warranties. On every model, wear parts such as the filter basket, brushes, and tracks are covered for 6 months, and Chasing requires proof of purchase from an authorized dealer for warranty service.

RoboticsSelect is an authorized Chasing dealer. Orders ship free to the contiguous 48 U.S. states, warranty claims run through our U.S.-based product-trained support team at support@roboticsselect.com or (412) 415-7375, and the standard 30-day return window applies to unopened, unused units. A price match policy and a financing page are also available.

The takeaway

The best Chasing cleaner is the one that fits your pool and your routine, not the longest spec sheet. The Hydro 3 handles a small pool with no app, the Hydro 3S adds planned coverage and scheduling, the Hydro 4 Corded removes the runtime limit, the Hydro 4 Battery keeps the deck clear on a larger pool, and the L1 Ultra maps the pool and manages itself from a dock. Compare all five in the Chasing pool cleaner collection and match the pool size rating first.